The refining of petroleum hydrocarbons often results in a refinery stream which will comprise mainly a gas or liquid stream of high butadiene content containing also thiolefinic and acetylenic hydrocarbons. The upgrading of the butadiene content in this fraction is possible only after removal of butyne and vinyl acetylene. One technique of upgrading the stream by removing the acetylenic compounds present is by selective hydrogenation. Techniques for selective hydrogenation of the acetylenics content are discussed in U.S. Pat. Nos. 4,587,369 and 4,493,906, both of which are incorporated herein by reference. The processes described in those patents rely primarily on a catalyst which in one instance will be a palladium on alumina catalyst, and in the other instance, a copper metal dispersed on gamma alumina. In the processes described therein it is, of course, desirable to minimize the loss of butadiene and butylene resulting from hydrogenation and oligomerization, and to reduce the rate of catalyst aging.
Accordingly a primary object of this invention is to provide a process wherein impure streams of butadiene can be purified by the hydrogenation of acetylenic compounds present therein using a catalyst agent. Still another object of this invention is to diminish the rate of catalyst aging. Another object of this invention is to provide a method for minimizing butadiene loss.